Many techniques have been developed to activate and/or control a device as a user approaches. For example, whether a users hand approaches a device or the user's attention is directed toward the device. One example of such a known technique is disclosed by U.S. Pat. No. 6,111,580. U.S. Pat. No. 6,111,580 discloses an input unit that attempts to determine whether a user wishes to interact with a device; that is, whether a user's attention is directed toward the device. If such a determination is made, the input unit then determines whether the user performs an act that corresponds to a command. The input unit then controls the device according to the command.
U.S. Pat. No. 6,111,580 discloses various different methods for determining whether a user's attention is directed toward the device, for example, detecting the direction of the user's gaze, detecting the utterance of a predetermined word in the voice of a user, detecting contact of a user on a pressure sensor or switch, detecting a full frontal view of a user's face (for instance, by symmetry) or detection of a specific gesture performed by a user.
However U.S. Pat. No. 6,111,580 requires a complex configuration of sensors in order to detect the user's attention and gesture to generate commands to control the device. Thus the system is inefficient requiring high power consumption and high processor usage.